Patent GB-978854-A (GB)
Title: New thiophosphoric esters, compositions containing same, and process for their production
IPC: C07D285/13
Filed: 1961-04-06
Abstract: The invention comprises thiophosphoric acid esters of the general formula:- <FORM:0978854/C1/1> wherein X, Y and Z independently of each other represent O or S atoms, R1 and R2 are the same or different C1-C3 alkyl groups and A is hydrogen, a C1-C7 alkyl radical the chain of which may be interrupted by an O or S atom, or is an unsubstituted or substituted, especially chlorinated, phenyl or benzyl radical or a heterocyclic radical bound by way of one of its carbon atoms. They may be obtained by reacting a compound of the formula:- <FORM:0978854/C1/2> wherein Hal is Cl or Br with a compound of the formula:- <FORM:0978854/C1/3> or with salts thereof e.g. the alkali metal or ammonium salts. The reaction can be carried out in an organic solvent e.g. acetone, butanone, methanol, ethanol, ethyl acetate or benzene at room temperature or at moderately elevated temperature e.g. between 20 DEG  and 80 DEG C.  Alkali hydroxides or carbonates can be used as acid binding agents.  When A is a heterocyclic radical it may be 2-furyl, 2-, 3- or 4-pyridyl, 2-thienyl or a 2-thiazolyl radical and when A is a substituted phenyl or benzyl radical, the substituents may (apart from halogen) be methyl, methoxy, methyl (or ethyl) mercapto nitro, or methylenedioxy radicals.  Several examples are given and the products have pesticidal properties (see Division A5).  The starting materials of Formula II may be obtained by reacting 1, 3, 4-oxadiazole-2(3H)-ones (or thiones), or 1, 3, 4-thiadiazole-2(3H)-ones (or thiones) of the general formula <FORM:0978854/C1/4> wherein A is as defined above with formaldehyde and treating the resulting 3-hydroxymethyl derivatives with phosphorus pentachloride, thionyl chloride or phosphorus tribromide.  The heterocyclic compounds of Formula IV can be obtained from carboxylic or thiocarboxylic acid hydrazides by reaction with phosgene or thiophosgene.  The compounds of formula IV containing sulphur can also be obtained by reacting a carboxylic acid hydrazide with carbon disulphide and an alkali metal hydroxide to form an alkali metal salt of an acyl dithio carbazic acid of the formula A-CO-NH-NH-CS-SH and converting the latter either (a) into a 1, 3, 4-oxadiazole-2(3H)-thione by boiling in alcohol while splitting off hydrogen sulphide or (b) into a 1, 3, 4-thiadiazole-2(3H)-thione by treating with sulphuric acid and then splitting off water. Several examples are given for the production of various compounds of Formula IV and of Formula II as well as the hydroxymethyl derivatives corresponding to the latter.ALSO:A pesticidal composition comprises a carrier and/or distributing agent and at least one compound having the general formula <FORM:0978854/A5-A6/1> wherein X, Y and Z independently of each other represent oxygen or sulphur atoms, R1 and R2 are the same or different C1-C3 alkyl groups and A is hydrogen, a C1-C7 alkyl radical the chain of which may be interrupted by an O or S atom, or is an unsubstituted or substituted, e.g. chlorinated, phenyl or benzyl radical or a heterocyclic radical bound by way of one of its C atoms (see Division C2).  When A is a heterocyclic radical the latter may be 2-furyl, 2-, 3- or 4-pyridyl, 2-thienyl or a 2-thiazolyl radical and when A is a substituted phenyl or benzyl radical the substituents apart from halogen may be methyl, methoxy methyl (or ethyl) mercaptomethyl, nitro or methylenedioxy radicals. The carriers may be solid, liquid or gaseous and the composition may be in the form of a dust, suspension, emulsion or solution which may contain a surface-active agent of the cationic, non-ionic or an ionic-type or a soap.  The composition may also be in a form suitable for use as an aerosol, smoke or mist.  An epoxide may be included as a stabilizer, specified expoxides being epichlorhydrin, cyclohexeneoxide, styrene oxide, and 1-phenoxy (or b -naphthoxy)-2,3-epoxypropane.  Other pesticidal agents may also be present, e.g. hexachlorocyclohexane, dichlorodiphenyltrichlorethane, "Toxaphene" (Registered Trade Mark), calcium arseniate, (p-nitrophenyl)-diethyl thiophosphate, (3 - chloro - 4 - nitrophenyl) - dimethyl thiophosphate, [2 - isopropyl - 4 - methyl - pyrimidyl - (6)] - diethyl thiophosphate, (b ,b  - dichlorovinyl) - dimethyl phosphate, (a  - hydroxy, b ,b ,b -trichloroethyl) phosphonic acid dimethyl ester, S-(1,2-dicarboethoxyethyl) - O,O - dimethyl dithiophosphate, S - (4 - chlorophenylmercaptomethyl) - O,O - diethyl dithiophosphate, S - (2,5 - dichlorophenylmercaptomethyl) - O,O - diethyl dithiophosphate, N - trichloromethane sulphenyl tetrahydrophthalimide, methane sulphone-N-trichloromethane sulphenyl-p-chloranilide, or sulphur. A herbicide may also be present.